CHROMITE 


Mining  and  Scientific  Press 

San  Francisco 

1918 


CHROMITE 


By  ALBERT  BURCH  and  SAMUEL  H.  DOLBEAR 


Sources  and  Uses. 

Why  Increased  Production  Within  the  United  States  is  a 
War  Necessity. 

Characteristics  and  Surface  Indications. 
Shape  of  Deposits. 
Origin. 

Distribution  of  Chrome  in  Deposits. 
Field  Determination  of  Chromite. 
Minerals  Mistaken  for  Chromite. 

Methods  and  Costs  of  Mining. 

Methods  and  Costs  of  Concentrating. 

Methods  and  Costs  of  Transportation. 

Proper  Capital  Investment. 

Methods  of  Financing  Operations. 

Markets,  Selling  Conditions,  Future. 
Prices. 
Contracts. 

How  to  Make  Shipments. 
Specifications  for  Marketable  Ore. 
Methods  of  Marketing. 
List  of  Purchasers. 

Sampling  and  Analysis  of  Chromite.     By  Abbot  A.  Hanks. 
The  Determination  of  Chromium  in  Chromite. 


387362 


FOREWORD 


This  pamphlet  has  been  written  in  response  to  a  con- 
stantly increasing  demand  for  information  regarding 
chromite,  its  occurrence  in  nature,  and  the  methods  to  be 
used  in  its  production  and  in  marketing.  Chromite  is 
one  of  the  most  important  of  the  so-called  war-minerals, 
and  the  necessity  for  stimulating  its  production  cannot 
be  over-rated.  Through  the  generosity  and  patriotism 
of  the  Mining  and  Sciem,tific  Press,  which  has  published 
this  pamphlet  at  its  own  expense,  it  is  possible  to  dis- 
tribute this  without  charge  to  those  seeking  information. 
Acknowledgment  is  also  made  to  Abbot  A.  Hanks  for 
the  chapter  on  sampling  and  analysis. 

Albert  Burch. 
Samuel  H.  Dolbear. 
July  1,  1918. 


Digitized  by  the  Internet  Archive 
•    in  2007  with  funding  from 
IVIicrosoft  Corporation 


http://www.archive.org/details/chromiteOOburcrich 


CHROMITE 


Sources  and  Uses 

Chromite,  or  chrome-iron  ore,  which  is  the  only  com- 
mercially valuable  ore  of  chromium,  is  found  in  Euro- 
pean and  Asiatic  Turkey,  Greece,  Russia,  India,  New 
Caledonia,  Rhodesia,  Canada,  Cuba,  and  the  United 
States.  Low-grade  ores  are  also  found  in  Germany,  and 
small  deposits  in  a  few  other  countries. 

For  many  years  most  of  the  ore  used  in  the  United 
States  came  from  Asiatic  Turkey,  with  the  exception  of 
the  small  amount  used  on  the  Pacific  Coast,  this  being 
mined  in  California.  Later,  with  the  discovery  of  large 
deposits  in  New  Caledonia,  that  island  became  the  chief 
source  of  supply,  not  only  for  the  United  States,  but  for 
Europe,  and  still  more  recently  a  considerable  quantity 
of  high-grade  ore  has  been  coming  from  Rhodesia. 

In  the  United  States  some  important  deposits  in  the 
Eastern  States  were  worked  several  years  ago,  but  have 
apparently  become  exhausted,  so  that  now  almost  the 
only  sources  of  domestic  ore  are  the  serpentine  areas  of 
California  and  Oregon,  if  we  exclude  from  consideration 
the  newly  discovered  deposits  of  Montana  and  Wyoming, 
the  importance  of  which  has  not  yet  been  demonstrated. 

The  chief  uses  of  chrome  ore  are 

(1)  As  an  alloy  for  hardening  and  toughening  steel, 

(2)  As  a  heat  and  acid-resisting  lining  for  steel- 
furnaces, 

(3)  For  making  dyes  to  color  cloth  (as,  for  instance, 
khaki),  and 

(4)  For  the  manufacture  of  chemicals  used  in  the  tan- 
ning of  leather. 

Substitutes  may  be  used  for  any  of  the  purposes 
named,  but  none  of  them  will  perform  exactly  the  same 
function  as  chromium ;  and,  in  order  to  use  them,  radical 
and  expensive  changes  will  have  to  be  made  in  manu- 
facturing equipment  and  methods. 


Why  Increased  Production  Within  the  United 
States  is  a  War  Necessity 

Chrome-steel  is  used  directly  in  the  manufacture  of 
axles,  springs,  etc.,  which  form  parts  of  gun-carriages, 
automobiles,  auto-trucks,  and  probably  the  famous 
*  tanks',  all  of  which  may  be  classed  as  'munitions  of 
war*. 

Chrome  bricks  and  raw  chrome  ores  are  used  to  line 
the  furnaces  that  turn  out  36,000,000  tons  of  steel  per 
annum,  for  no  substitute  is  known  the  use  of  which  will 
not  result  in  reducing  the  daily  capacity  of  these 
furnaces. 

Chromium  chemicals  are  used  for  dyeing  the  cloth  that 
goes  into  the  manufacture  of  soldiers'  uniforms  and  for 
tanning  the  leather  from  which  their  shoes  are  made. 

If  the  ore  for  these  uses  is  not  produced  within  the 
United  States,  or  Canada,  it  must  come  in  ships  from 
abroad,  and.  as  the  supply  obtainable  from  Canada  is 
quite  small,  and  the  output  from  Cuba  only  just  begin- 
ning, this  means  that  it  must  come  from  New  Caledonia 
and  Rhodesia,  the  European  and  Asiatic  supplies  being 
either  in  enemy  hands  or  in  such  locations  that  the  ports 
of  export  are  closed  by  enemy  fortifications.  The  fact 
that  the  winning  of  the  war  depends  upon  the  number 
of  men  the  United  States  can  put  in  the  field  in  Europe 
is  now  so  well  known  as  to  require  no  comment,  and  it 
is  also  understood  that  the  only  limit  to  the  number  of 
men  we  can  send  to  the  front  is  the  number  of  ships  to 
transport  them  and  keep  them  supplied  with  munitions 
and  food.  For  this  purpose,  a  ship  diverted  from  un- 
necessary traffic  is  worth  even  more  than  a  ship  built, 
because,  with  its  crew,  it  is  immediately  available ;  and 
because  it  takes  so  much  longer  for  a  ship  to  make  the 
round  trip  with  a  cargo  of  chrome  ore  between  the  United 
States  and  the  ports  of  New  Caledonia  and  South  Africa 
than  between  New  York  and  the  French  ports,  it  is  esti- 
mated that  releasing  such  a  ship  is  equivalent  to  the 
building  of  five.  Reducing  this  to  terms  of  chrome  ore, 
each  thousand  tons  of  such  ore  produced  in  California 
will  enable  us  to  face  the  Kaiser  with  two  thousand  more 
men. 

~6— 


Methods  and  Costs  of  Mining 

The  sudden  and  rapid  growth  of  the  chrome-mining 
industry  in  California  and  Oregon  has  resulted  in  draw- 
ing into  it  two  classes  of  men,  namely,  those  who  have 
had  no  previous  mining  experience  whatever,  and  those 
who  have  gained  their  experience  from  mining  other 
ores.  It  is  hoped  the  remarks  that  follow  may  in  some 
cases  be  of  use  to  the  one  class,  and  in  some  cases  to  the 
other.  To  those  who  have  had  no  experience,  we  would 
say:  get,  if  possible,  a  good  mine  foreman  who  has 
learned  his  business  from  the  bottom  up,  and  who  has 
the  knack  of  acquiring  and  holding  th6  respect  and  good- 
will of  his  men.  The  services  of  such  a  man  are  invalu- 
able, and  the  price  you  can  afford  to  pay  for  them  is 
limited  only  by  the  magnitude  of  the  operation.  Next 
provide  as  good  quarters  for  your  men  as  the  circum- 
stances and  probable  duration  of  the  operation  will  per- 
mit, and  then  see  that  they  get  good  food,  even  if  you 
seem  to  be  losing  money  by  supplying  it. 

In  detail,  the  proper  methods  of  mining  will  be  gov- 
erned by  the  circumstances  surrounding  each  venture 
and  these  will  vary  quite  as  much  between  different 
mines  as  they  will  between  those  of  enterprises  based 
upon  the  exploitation  of  other  minerals,  but  the  chapter 
describing  the  irregularity  and  uncertainty  of  chrome 
deposits  emphasizes  the  fact  that  in  the  mining  of  chro- 
mite  more  than  that  of  any  other  mineral,  the  most  im- 
portant thing  is  to  follow  the  ore.  In  doing  this,  any  one 
of  three  methods  may  be  available,  namely,  open-cut, 
tunnel,  or  shaft,  of  which  the  first  is  always  the  cheapest 
and  the  last  the  most  expensive. 

An  outcrop,  no  matter  how  small,  may  be  the  only 
surface  exposure  of  a  large  lens,  or  you  may  be  able  to 
see  in  it  ''all  the  ore  there  is".  When  such  an  outcrop 
is  found  on  a  hillside,  an  open-cut  should  be  started 
upon  it,  and,  if  on  level  ground,  a  shaft  should  be  started 
in  the  ore.  In  no  case  should  a  tunnel  be  started  in 
barren  ground  for  the  purpose  of  driving  under  an  out- 
crop, until  it  has  been  demonstrated  by  shaft  or  winze 
how  deep  the  deposit  goes,  and  then  only  after  sufficient 


other  work  has  been  done  to  prove  that  enough  ore  exists 
to  enable  one  to  repay  the  cost  of  the  tunnel  out  of  the 
difference  between  the  cost  of  hoisting  or  shoveling  it  and 
that  of  handling  it  by  overhead  stoping  from  the  tunnel- 
level. 

Again,  in  the  case  of  a  deposit  that  must  be  worked 
through  a  shaft,  two  questions  may  arise :  ( 1 )  should  the 
working  shaft  be  located  in  the  orebody  itself,  or  on  one 
side;  and  (2)  what  hoisting  equipment  should  be  used? 

The  first  question  cannot  be  answered  until  work  has 
been  done  on  the  orebody  itself  to  determine  its  size  and 
shape.  Should  it  prove  not  to  be  more  than  fifteen  or 
twenty  feet  deep,  the  hoisting  could  well  be  done  through 
an  opening  in  the  ore  itself,  for  a  windlass  would  prob- 
ably be  used  and  it  could  be  shifted  from  one  part  of 
the  deposit  to  another  without  great  expense.  Should 
the  ore  go  to  a  greater  depth,  then  its  width,  the  shape 
at  the  top,  and  the  firmness  of  the  walls  would  determine 
where  the  shaft  should  be  sunk ;  for,  if  the  orebody  is 
not  more  than  about  ten  feet  wide  at  the  top,  does  not 
expand  with  depth,  and  has  walls  of  fairly  firm  rock, 
then  the  head-frame  may  be  placed  on  stringers  spanning 
the  entire  opening  and  no  outside  shaft  will  be  needed. 
On  the  other  hand,  should  any  one  of  these  conditions  be 
reversed,  it  would  probably  be  wise,  in  the  case  of  a  large 
orebody,  to  sink  a  shaft  in  the  country-rock  a  short 
distance  from  the  deposit  after  the  preliminary  prospect- 
ing in  the  ore  had  been  performed. 

The  second  question  must  be  determined  by  the  quan- 
tity of  ore  and  the  depth  from  which  it  is  to  be  hoisted. 
For  depths  not  greatly  exceeding  twenty  feet,  hoisting 
by  windlass  is  probably  as  cheap  as  by  any  other  method, 
though  even  to  this  depth  should  the  orebody  be  large 
it  might  pay  to  carry  an  inclined  track  down  through 
the  middle  of  the  deposit  and  hoist  by  gasoline-engine, 
steam,  or,  in  a  remote  district,  a  horse-whim  or  'whip'. 
No  hard  and  fast  rule  can  be  established,  but,  as  in  the 
case  of  a  proposed  extraction  tunnel,  the  probable  num- 
ber of  tons  available  should  be  multiplied  by  the  cost 
per  ton  of  hoisting  when  employing  the  method  involv- 
ing the  smallest  investment  for  equipment,  and  by  the 

—8— 


cost  per  ton  for  each  more  expensive  equipment.  When- 
ever the  difference  is  sufficient  to  re-pay  the  cost  of  the 
machinery  less  its  salvage  value,  it  should  be  installed. 
Costs  of  hoisting  by  different  methods  vary  so  greatly 
with  different  localities,  depths,  and  tonnages,  that  no 
attempt  will  be  made  here  to  list  them. 

Most  of  the  chromite  deposits  of  California  and 
Oregon  are  so  small  that  drilling  by  hand  is  the  method 
that  must  be  adopted,  and  actual  mining  by  this  method 
is  not  as  a  rule  much  more  expensive  per  ton  of  ore 
broken  than  by  machine-drilling;  but  the  latter  method 
is  much  more  rapid,  thus  reducing  the  overhead  expense, 
and  where  labor  is  scarce,  as  it  is  in  war  times,  the  differ- 
ence in  the  number  of  men  necessary  to  produce  a  given 
tonnage  is  important.  Therefore,  whenever  a  deposit  is 
found  that  appears  large  enough  (dividing  the  cost  of 
installation  by  the  probable  tonnage  available),  we  would 
advise  the  use  of  compressed-air  drills,  for  driving  which 
there  are  several  makes  of  portable  and  semi-portable 
air-compressors.  It  would  be  manifestly  unwise,  how- 
ever, to  wait  60  days  for  the  erection  of  a  compressed- 
air  plant  on  a  mine  that  could  be  worked  out  by  hand  in 
that  length  of  time. 

When  the  deposit  is  not  large  enough  to  justify  build- 
ing a  concentrator  for  the  purpose  of  separating  ore 
from  waste,  it  will  be  necessary  to  cob  and  sort  the  ore 
in  order  to  produce  a  shipping  product.  In  such  mines 
a  good  foreman  can  frequently  economize  on  the  subse- 
quent sorting  by  having  his  holes  so  placed  as  to  break 
the  spots  of  clean  ore  separate  from  the  mixed  material. 
This  can  be  done  more  readily  where  hand-drilling  is 
used  instead  of  machine-work.  For  the  actual  cobbing 
it  pays  to  provide  special  hammers  formed  like  a  geolo- 
gist's hammer,  but  a  little  heavier;  and  it  also  pays  to 
dump  the  ore  over  an  inclined  screen,  so  that  the  sorting 
is  done  upon  the  coarser  material  only.  It  also  pays  to 
spray  the  ore  with  water  before  sorting,  and  it  is  sur- 
prising how  much  spraying  can  be  done  through  fine 
holes  in  a  tin  can  from  a  single  barrel  of  water.  It  may 
be  found  that  the  screening  from  one  lot  of  ore  is  suffi- 
ciently good  to  be  shipped  with  the  selected  ore  whereas 

—9— 


that  from  the  next  lot  will  fall  short  of  the  requirements. 
If  a  good  foreman  be  allowed,  at  the  beginning  of  an 
operation,  to  take  frequent  samples  of  the  screening  for 
analysis,  he  will  soon  be  able  to  judge  fairly  well  whether 
a  given  pile  should  be  shipped  or  put  aside  for  concen- 
trating later. 

The  cost  of  mining,  the  product  from  a  chrome  mine 
in  California  varies  within  wide  limits,  although  the 
actual  breaking  and  tramming  of  the  material  from  a 
medium  orebody  should  not  exceed  the  following  prices 
per  ton : 

Hand-drilling'  Machine-work 

Open-cut     »1.50  $1.10 

Overhead   sloping-   from   tunnel 2.25  1.75 

Overhead  stoping  and  hoisting-  through  shaft.  3.00  2.50 

Underhand    sloping:     6.00  5.00 

Added  to  these  costs,  however,  are  numerous  items  of 
overhead  expense,  which  are  frequently  overlooked,  for 
example,  amortization  of  plant,  workmen's  compensa- 
tion insurance,  taxes,  loss  on  boarding  house,  superin- 
tendence, sampling  and  analysis  of  samples,  and  various 
other  items,  which,  for  even  a  large  operation  may  easily 
amount  to  a  dollar  per  ton  and  for  small  ones  may 
amount  to  several  dollars  per  ton.  What  causes  the 
greatest  variation  in  the  cost  of  mining,  aside  from  dif- 
ferences in  the  size  and  form  of  the  orebodies,  is  the  rela- 
tion between  quantity  of  ore  mined  and  of  product  ship- 
ped, for  according  as  the  ore  is  clean  or  badly  mixed 
with  waste,  the  sorting  may  range  from  as  low  as  two 
dollars  per  ton  up  to  as  much  as  twenty. 

Methods  and  Costs  of  Concentrating 

Many  deposits  of  chromite  that  are  too  low-grade  to 
be  marketable  will  yield  a  good  product  as  the  result  of 
concentration,  but,  before  building  a  mill  for  that  pur- 
pose, careful  consideration  should  be  given  to  some  im- 
portant questions. 

(1)  What  profit  per  ton  will  the  ore  yield  after  pay- 
ing all  costs,  including  mining  and  concentration  f 

(2)  How  many  tons  are  available,  and  is  the  quantity 
sufficient  to  re-pay  the  cost  of  the  mill,  leaving  a  profit  ? 

(3)  Is  there  an  assured  supply  of  water  sufficient  for 

—10— 


the  tonnage  to  be  treated?     About  seven  tons  of  water 
is  required  for  each  ton  of  ore. 

(4)  Is  the  ore  itself  amenable  to  concentration? 
What  percentage  of  recovery  and  what  grade  of  concen- 
trate can  be  obtained? 

(5)  What  is  the  type  of  equipment  best  adapted  to 
the  treatment  of  this  particular  ore  ? 

The  gravity  concentration  of  chrome  ores  is  an  ex- 
tremely simple  operation,  because  the  specific  gravity  of 
chromite  is  nearly  double  that  of  the  usual  gangue,  which 
is  mostly  serpentine.  The  grade  of  the  concentrate  is 
determined  not  so  much  by  the  percentage  of  gangue  re- 
maining in  it  as  by  the  grade  of  the  clean  mineral  itself, 
which  is  variable. 

For  the  final  crushing  of  the  ore  after  it  has  passed 
through  the  ordinary  rock-breaker,  a  machine  should  be 
selected  that  will  give  a  maximum  of  crushing  capacity 
with  a  minimum  of  sliming.  For  this  purpose  we  favor 
rolls.  This  practice  has  not  been  followed,  however,  by 
most  mill-builders  in  California,  where  ball-mills  and 
even  stamps  have  been  used  for  the  final  crushing;  but 
whether  this  has  been  the  result  of  careful  design  or  due 
to  the  necessity  for  quick  delivery  of  equipment  is  not 
known — the  latter  reason  seems  the  more  probable.  Fol- 
lowing the  final  crushing  it  has  been  the  general  prac- 
tice to  pass  the  material  through  some  type  of  classifier  to 
separate  the  sand  from  the  slime.  The  sand  is  then 
passed  over  tables  that  discharge  concentrate,  middling, 
and  tailing,  while  the  slime  is  treated  on  tables  the  prod- 
ucts of  which  are  concentrate  and  tailing.  The  middling 
from  the  sand-tables,  without  further  grinding,  is  re- 
concentrated  on  another  set  of  sand-tables. 

Such  a  concentratol-,  including  a  rough  building  and 
gasoline-engines  for  power,  can  now  be  erected  at  points 
near  a  railroad  in  California  or  Oregon  for  about  $300 
per -ton  of  daily  capacity,  or,  say,  $15,000  for  a  50-ton 
mill. 

It  is  our  belief  that,  because  of  the  difference  in  the 
character  of  the  ore  in  various  deposits,  such  an  im- 
portant thing  as  the  construction  of  a  mill  should  not  be 
undertaken  without  first  having  made  preliminary  tests 

—11— 


upon  the  ore  in  a  properly  operated  testing-plant  and 
that  then  both  the  crushing  and  concentrating  equipment 
should  be  selected  to  fit  the  requirements  of  the  ore  to  be 
treated,  and  as  most  of  the  chrome  ore  that  has  come 
under  our  observation  has  been  comparatively  coai*se  in 
texture  it  is  believed  that  for  most  cases,  the  equipment 
desirable  will  be  about  as  follows:  Rock-breaker,  rolls 
working  in  closed  circuit  with  a  4  to  6-mm.  trommel,  fine 
jigs,  rolls  for  jig-middling,  working  in  closed  circuit 
with  Bunker  Hill  or  Callow  screen,  classifier  dividing 
the  product  to  sand  and  slime  tables,  stationary  canvas 
plant  after  slime-tables.  Such  a  plant  should  not  cost 
much  more  than  the  other  type  and  on  most  chrome  ores 
the  percentage  of  recovery  should  be  higher.  Naturally, 
where  fine  grinding  is  really  required  for  the  purpose  of 
liberating  the  mineral,  ball-mills  will  be  introduced  for 
this  work. 

The  recovery  of  chrome  ore  by  concentration  in  Cali- 
fornia should  be  fully  75%  of  the  mineral;  with  careful 
work  and  some  refinements  in  practice  it  might  be 
brought  well  above  80%.  Too  much  money  cannot,  how- 
ever, be  expended  upon  refinements  for  the  benefit  of  a 
short-lived  enterprise.  The  cost  of  concentration  may  be 
expected  to  range  from  less  than  one  dollar  per  ton  for 
a  well-constructed  100-ton  plant  driven  by  cheap  electric 
power  up  to  two  dollars,  or  more,  for  a  small  poorly  con- 
structed mill  using  gasoline-power. 

Methods  and  Costs  of  Transportation 

Under  this  heading  we  must  note  again  the  great  dif- 
ference in  circumstances  affecting  individual  cases.  One 
mine  might  be  large  enough  and  rich  enough  to  justify 
the  construction  of  several  miles  of  expensive  truck- 
road,  or  even  railroad,  while  a  mile  of  trail  construction 
might  be  more  than  another  one  could  stand.  Whether 
a  man  shall  'sled'  his  ore  down  from  a  hill  at  a  cost  of 
$10  per  ton  instead  of  building  a  road  for  $2000  over 
which  it  will  cost  him  $2  per  ton  to  haul  it,  will  depend 
upon  whether  he  has  at  least  one-eighth  of  2000  tons  to 
haul.  This  applies  to  all  other  questions  relating  to  the 
kind  of  transportation  to  be  used. 

—12— 


The  following  figures,  as  to  costs  in  California  and 
Oregon,  are  believed  to  be  fairly  accurate  at  the  present 
time : 

Per  ton-mile 

Pack-animals    over    roug-h    mountain-trail    at    200    lb.    per 

animal  where  all  the  feed  must  be  imported $2.50  to  $3.50 

Pack-animals    over    rough    mountain-trail    at    200    lb.    per 

animal  when  g^razingr  is  good 2.00  to     2.50 

Hauling  by  team  over  mountain-roads  too  steep  for  motor- 
trucks at  1000  to  1200  lb.  per  animal 0.60  to     0.60 

Motor-trucks   over  hard  mountain-roads 0.25  to     0.40 

Pack-animals  can  average  not  more  than  15  miles  per 
day  when  loaded,  and  about  18  miles  is  a  good  day^s 
work  for  a  freight  team. 

For  pack-animals  and  freight  teams  round  trips  con- 
suming less  than  one  day  are  less  economical  in  cost  per 
ton-mile  than  those  requiring  more  time ;  and  for  motor- 
trucks round  trips  requiring  exactly  one  day  are  the 
most  economical.  For  trips  of  one  day  or  less  kyaks  in- 
stead of  bags  are  recommended  for  packing,  because 
they  are  so  much  cheaper  and  easier  to  load  and  unload. 

The  cost  of  roads  and  trails  varies  so  greatly  in  moun- 
tainous regions  that  it  is  not  advisable  to  begin  any  im- 
portant construction  of  this  kind  without  a  survey  and 
an  estimate  of  cost  by  a  competent  engineer. 

Proper  Capital  Investment 

If  the  reader  has  studied  the  chapter  describing  the 
nature  of  chrome  deposits,  he  will  realize  that  the  out- 
right purchase  of  undeveloped  prospects  and  even  their 
development  if  situated  at  points  remote  from  transpor- 
tation, is  a  risky  business;  but,  aside  from  the  uncer- 
tainty of  the  market,  it  is  perhaps  no  more  risky  than 
that  of  the  average  mining  exploration  and  not  nearly 
so  risky  in  proportion  to  the  capital  invested  as  that  of 
the  average  prospector  who  stakes  his  entire  fortune 
(which  happens  to  be  his  life)  on  the  chance  of  making 
a  good  discovery. 

A  safer  plan,  and  one  fairer  to  the  investor,  is  the 
leasing  system,  with  or  without  an  option  to  purchase; 
and,  except  for  unusually  promising  ground  to  be  had  for 
a  low  figure,  it  is  the  only  one  that  we  would  be  disposed 
to  recommend.     The  risk  will  then  be  confined  to  the 

—13—    . 


money  expended  for. development  and  as  much  more  as 
the  gambling  instinct  may  cause  a  man  to  expend  in 
equipment  or  road-building  before  he  has  actually 
blocked  out  enough  ore  to  pay  for  the  money  spent.  The 
royalty  should  not  exceed  10%  of  the  value  of  the  ore  at 
the  mine.  At  the  risk  of  being  ultra-conservative,  we 
would  say  that  even  in  the  interest  of  quick  production, 
and  presumably  of  quick  profit,  the  miner  should  not  be- 
gin the  construction  of  a  road  to  haul  his  product  until 
at  least  half  the  cost  of  the  road  is  in  sight  in  the  form  of 
ore  mined  or  exposed,  and  with  more  than  one  face  in 
good  ore ;  and  that  he  should  not  begin  the  construction 
of  a  mill  until  the  whole  price  is  in  sight.  The  reason  for 
this  last  proviso  is  that  the  margin  of  operating  profit  on 
concentrating  ore  is  usually  much  smaller  than  on  the 
shipping  grades  and  the  other  risks  incident  to  the  busi- 
ness are  large  enough. 

Characteristics  and  Surface  Indications 

Chrome  ore  is  found  associated  with  basic  magnesian 
rocks,  usually  serpentine.  It  is,  therefore,  a  waste  of 
time  to  seek  deposits  in  regions  where  no  serpentine 
exists.  Wherever  serpentine  is  found,  chrome  deposits 
may  exist  and  prospecting  is  warranted. 

The  ore  is  heavy  and  dark.  Float  is  usually  found 
near  the  deposits,  either  in  the  gulches  or  on  the  hill- 
sides immediately  below  them.  It  may  be  necessary  to 
dig  shallow  trenches  cross-cutting  the  zone  where  'float' 
is  believed  to  exist ;  the  soil  and  rock  shoveled  from  such 
trenches  should  be  carefully  examined  for  ore.  When 
'float'  is  found,  it  should  be  followed  to  the  point  where 
it  is  most  abundant,  and  then,  if  no  outcrop  is  seen, 
trenches  must  be  dug  in  order  to  uncover  the  orebody. 
Occasionally  float  cannot  be  traced  to  ore  in  place.  This 
is  due  to  the  fact  that  the  orebody  has  been  completely 
eroded. 

The  prospector  should  not  let  this  discourage  him. 
Hundreds  of  tons  of  such  fragmental  mineral  have 
been  shipped.  The  ground  may  be  plowed  and  the 
soil  screened,  so  that  the  chrome  may  be  sorted  from 
the  waste  by  hand.     If  no  plow  is  available,  pick  and 

—14— 


shovel  work  may  take  its  place.  The  mining  of  float  ore 
frequently  yields  a  high-grade  product  and  may  prove  a 
most  profitable  operation. 

Miners  are  beginning  to  understand  the  characteristics 
of  these  deposits.     There  are,  however,  manj^  new  ones 


lif^^^^-^-^aiTiJSirfi*  %*wrai.. 


VAUGHN   CHROME  MINE.      FROM  THIS  DEPOSIT  WAS 
COLLECTED  1200  TONS  OF  FLOAT  CHROME 


being  worked  by  those  less  experienced,  who  make  errors 
in  estimating  the  possible  tonnage. 

In  many  cases  the  miner  considers  he  is  opening  an 
orebody  occurring  in  more  or  less  irregular  veins,  and 
that  the  origin  of  the  ore  is  similar  to  that  of  quartz 
veins.  Outcrops  may  be  found  for  a  distance  of  several 
hundred  feet,  and  in  such  alignment  as  to  give  the  im- 
pression that  the  deposits  are  continuous.     The  handy 

—15— 


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pencil  is  then  put  to  work  to  calculate  that  the  average 
width  of  the  orebody  is,  say,  11  ft.,  the  'vein'  can  be 
traced  for  800  ft.,  and  the  ore  ought  to  persist  at  least 
20  ft.  below  the  surface,  giving,  therefore,  a  total  of 
176,000  cu.  ft.,  which,  at  10  cu.  ft.  per  ton,  makes  17,600 
tons  of  ore.     This  amount  is  then  offered  for  sale. 


O'UtC-r-OJo 


Flo  cut 


--SeTrperttirx^G 


f<fclJ>|:,>»*^. 


SECTION   OF   SERPENTINE   HILL   SHOWING   IRREGULAR  OREBODIES 


Chromite  does  not  occur  in  veins.  In  a  few  cases  long 
narrow  lenses  are  observed  extending  100  ft.  or  more 
along  the  surface,  and  a  few  feet  wide.  The  depth  of  the 
orebody  may  be  five  feet  or  it  may  be  50  or  more.  This 
can  be  determined  only  by  development  work;  this 
usually  involves  mining  the  ore,  which,  of  course,  necessi- 
tates following  the  orebody. 

—18— 


Shape  of  Deposits.  The  irregular  shape  of  chrome 
deposits  often  presents  puzzling  problems.  Figure  4  is 
an  illustration  of  the  peculiar  shape  of  one  deposit.  The 
section  extends  through  a  serpentine  hill  containing 
chrome.  The  lower  deposit  may  be  entirely  disconnected 
from  the  upper.  In  such  a  case  the  lower  deposit  might 
not  be  found  after  the  upper  had  been  exhausted. 
"When  a  deposit  'pinches  out',  a  good  rule  to  follow  is  to 
dig  a  little  further  before  abandoning  the  mine.  Under 
no  circumstances  should  a  'stringer',  a  small  ore-shoot, 
be  left  unexplored  in  the  face  of  the  working.  While  it 
may  not  pay  to  mine  so  small  a  shoot,  dig  it  out,  as  it 
may  lead  to  another  lens.  We  have  followed  this  rule, 
and  have  been  handsomely  rewarded  for  so  doing. 

Origin.  To  understand  why  estimates  of  chrome  ore 
cannot  be  prepared  in  the  manner  stated,  it  is  necessary 
to  know  something  about  its  origin.  When  two  sub- 
stances, one  of  wiiich  is  more  soluble  than  the  other,  are 
dissolved  in  water,  and  the  water  is  then  evaporated,  the 
least  soluble  substance  will  crystallize  out  first.  During 
the  period  when  the  earth's  crust  was  forming,  chrome 
was  in  solution,  not  in  water,  but  in  the  molten  magma 
which  formed  rock  on  cooling.  Chrome,  being  less  soluble 
than  other  substances  present,  was  one  of  the  first  to 
crystallize  from  the  magmatic  solution.  During  this 
crystallization,  the  particles  aggregated  in  irregular 
masses.  When  the  cooling  process  was  complete,  and  the 
entire  mass  had  become  solidified,  these  irregular  bodies, 
which  are  designated  lenses,  were  probably  near  the 
bottom  of  the  formation  in  which  they  are  found.  As 
the  weight  of  chrome  ore  is  much  greater  than  that  of 
the  rocks  in  which  it  is  found,  it  seems  probable  that  it 
settled  to  lower  depths  during  its  aggregation.  If  this 
be  accepted  as  correct,  the  question  arises,  'How  did  it 
reach  the  surface?'  Folding,  faulting,  and  weathering 
are  the  forces  responsible  for  its  exposure  at  the  surface. 

In  Fig.  1  the  lens  of  ore  is  shown  in  its  normal  position 
on  cooling;  later  folding  resulted  in  the  mass  assuming 
the  position  shown  in  Fig.  2 ;  dynamic  agencies,  followed 
by  erosion,  resulted  in  the  condition  seen  in  Fig.  3. 
The   dotted  lines  indicate  the  former  position  of  the 

—19— 


,  1. 

^-Ut-^ 

, 

^,-iXtL 

,! 

] 

nV 

,  '  ,1 

,  U-,  , 

T^^^ 

itir 

1  1 

I  1   J 

1 

Ftp.  1 


Fig.  5 


rome  \jk 


0. 


rocks  that  concealed  the  deposit  as  shown  in  Fig.  1  and 
2.  The  dark  portion  represents  the  consolidated  mass 
of  ore,  surrounded  by  smaller  bodies  and   segregated 


—20— 


particles,  which,  attracted  toward  the  main  orebody,  did 
not  reach  it  because  the  progress  was  impeded  by  gradual 
solidification  of  the  magma  to  form  solid  rock. 

All  chrome  miners  are  familiar  with  the  gradual  in- 
crease in  the  amount  of  waste-rock  in  their  ore  as  the 
limits  of  their  deposits  are  reached.  Occasionally  a  de- 
posit is  found  in  which  the  line  between  the  ore  and  wall- 
rock  is  distinct,  sometimes  separated  by  'gouge'  or 
'miner's  talc'.  When  no  chrome  ore  is  found  in  the 
wall-rock  immediately  adjoining  the  orebody,  and  gouge 
is  present,  it  may  indicate  that  the  original  wall-rock 
has  been  removed  by  displacement.  The  ore  along  the 
wall  may  be  fluted  or  grooved,  and  if  the  disturbance 
has  been  sufficient,  the  orebody  may  be  coarsely  frac- 
tured, or  even  so  finely  crushed  as  to  make  it  friable, 
that  is,  capable  of  being  disintegrated  by  compression  in 
the  hand.  Otherwise,  if  no  chrome  is  present  in  the 
wall-rock,  it  may  be  due  to  earlier  genetic  causes.  Some 
magmas  were  undoubtedly  more  fluid  than  others,  just 
as  some  smelter  slags  run  freely  while  others  are  so  slug- 
gish that  they  freeze  readily  at  the  tuyeres.  In  a  partic- 
ularly fluid  magma  there  would  be  flow-currents  just  as 
there  are  in  water,  these  tending  to  carry  away  chromite 
particles  which  had  not  yet  been  consolidated  with  the 
main  mass  of  chromite.  For  this  reason  I  conclude  that 
the  largest  deposits  of  chrome  were  probably  formed  in 
magmas  relatively  free  from  flow  currents.  Chrome  ore 
is  always  found  in  basic-igneous  rocks,  such  as  peridotite 
or  its  altered  form,  serpentine.  This  is  probably  because 
chromium  is  more  soluble  in  basic  than  in  acid  magmas. 

Distribution  op  Chrome  in  Deposits.  All  parts  of 
chrome  deposits  are  not  of  equal  grade.  The  question 
has  been  asked,  'What  may  be  expected  to  be  the  highest 
grade?'  In  most  deposits  the  ore  near  the  walls  or  the 
bottom  is  less  pure  than  that  in  the  main  orebody.  How- 
ever, there  is  much  variation ;  and  there  is  no  rule  to  fol- 
low. This  irregularity  probably  results  from  minor  in- 
fluences during  the  period  of  formation.  The  principal 
impurity  is  not  necessarily  silica;  it  may  be  iron,  mag- 
nesia, or  alumina.  If  iron  be  present  as  magnetite,  the 
ore  may  be  heavy  and  black,  and  may  appear  to  the  eye 

—21— 


.  to  be  high-grade,  yet  actually  low  in  chromic  oxide. 
Some  good  ore  is  found  with  a  film  of  magnesium  car- 
bonate, or  silicate,  so  that  it  is  white  in  appearance,  and 
such  ore  has  been  condemned  for  that  reason,  because  it 
was  considered  to  contain  too  much  silica.  It  is  impor- 
tant to  remember  this:  You  cannot  make  an  optical 
analysis  of  chrome  ore. 

Field  Determination  of  Chromite.  Familiarize 
yourself  with  the  appearance  of  typical  chrome  ore. 
Scratch  a  piece  of  the  suspected  ore  with  a  knife,  deep 
enough  to  penetrate  any  surface  film  of  foreign  material. 
If  the  streak  is  dark-brown,  the  material  may  be  chrome. 
If  the  prospector  will  provide  himself  with  a  spirit 
lamp,  two  inches  of  platinum  wire  fused  into  the  end  of 
a  short  glass  tube,  and  an  ounce  of  borax,  he  can  make  a 
fair  determination.  The  operation  is  as  follows:  Crush 
a  small  piece  of  the  ore  to  a  powder;  bend  a  small  loop 
at  the  end  of  the  platinum  wire;  heat  the  wire  in  the 
flame,  and  dip  it  in  the  borax.  Some  borax  will  stick  to 
the  loop.  Melt  this  in  the  flame,  and  continue  dipping 
in  the  powdered  borax  and  melting  it  until  the  loop  has 
become  filled  with  a  bead  of  colorless  borax-glass.  Heat 
the  bead  to  redness,  and,  while  hot,  place  it  against  the 
crushed  ore  until  a  few  particles  adhere  to  the  bead. 
Hold  this  in  the  flame  until  the  particles  are  entirely 
dissolved  in  the  borax,  allow  it  to  cool,  and  then  the 
bead,  if  chromium  is  present,  will  have  a  bright  green 
color.  Having  determined  that  chromium  is  present, 
send  the  sample  to  a  reputable  chemist  and  ask  him  to 
determine  the  amount  of  chromic  oxide  and  silica.  The 
ore-buyer  must  know  the  percentages  of  these  two  ma- 
terials before  he  can  go  further. 

Minerals  Mistaken  for  Chromite.  Magnetite,  or 
magnetic  iron  ore,  is  frequently  mistaken  for  chrome 
ore.  It  is  dense  black,  highly  magnetic,  and  of  about 
the  same  weight  as  chromite.  It  is  much  harder,  how- 
ever, and  can  be  scratched  with  a  pocket-knife  only  with 
difficulty,  and  it  does  not  show  the  brown  streak.  It  may 
be  distinguished  also  by  crushing  to  the  size  of  a  pea. 
If  it  can  be  picked  up  by  a  magnet  it  is  not  chromite. 

Hematite,  another  ore  of  iron,  is  sometimes  mistaken 

—22— 


for  chromite.  It  is  usually  softer,  and  has  a  reddish 
brown  streak,  quite  different  from  that  of  chromite. 

Homblende-picrite,  a  rock  that  is  dark-green  to  black, 
and  quite  heavy,  is  frequently  found  in  chrome  dis- 
tricts. Hornblende  may  be  similar  in  appearance.  The 
simple  way  to  distinguish  these  rocks  from  chromite  is 
to  scratch  them  with  a  pocket-knife ;  the  streak  is  grayish 
to  greenish-white. 

Methods  of  Financing  Operations.  The  prospector 
finding  a  chrome  deposit  usually  needs  financial  help  to 
develop  it  and  put  the  ore  on  the  cars.  Ore  placed  on 
railroad  cars  is  as  good  as  cash,  for  the  owner  can  at  once 
get  payment  for  the  shipment,  as  explained  in  the  sec- 
tion on  marketing.  Prior  to  that  time,  however,  one  of 
two  methods  is  commonly  employed.  The  owner  of  the 
deposit  may  seek  a  partner  who,  for  an  interest  in  the 
mine  ranging  from  25  to  75%,  will  furnish  the  neces- 
sary funds.  Whether  such  an  interest  should  be  25% 
or  more  may  be  determined  by  the  visible  profit  to  be 
made,  and  by  the  ability  of  the  prospector  as  a  trader. 
Funds  are  usually  required  to  build  roads  to  make  the 
ore  available  for  shipment,  and  sometimes  for  sled-trails 
or  pack-trails  which  may  be  used  for  a  part,  if  not  all,  of 
the  distance.  "When  the  ore  in  sight  is  small,  and  this  is 
usually  the  case,  the  prospector  should  be  satisfied  to 
start  operations  on  a  small  scale,  purchasing  only  such 
picks,  shovels,  and  drills  as  are  necessary  to  extract 
enough  ore  for  the  first  carload.  When  that  has  been 
done,  the  shipment,  if  the  ore  is  a  fair  grade,  will  provide 
$2000  or  more  as  working  capital,  with  which  to  expand 
the  work.  To  secure  funds  enough  to  buy  hoists,  cable- 
ways,  or  other  elaborate  machinery,  will  necessitate  the 
spending  of  time  in  promotion  that  should  be  used  in 
mining.  Financing  small  operations  as  corporate  enter- 
prises, and  selling  stock  to  get  funds,  is  usually  unsuc- 
cessful and  is  not  to  be  recommended. 

Several  of  the  larger  purchasers  of  chrome  ore  are 
willing  to  loan  money  to  operators  on  contracts  for  the 
output  of  the  mine.  The  ore  available  must,  of  course, 
justify  the  amount  of  the  loan,  which  may  be  as  much  as 
a  quarter  to  a  half  of  the  value  of  the  ore  developed. 

—23— 


It  is  also  necessary  to  know  that  the  money  loaned  will 
be  used  in  mining,  building  roads,  in  providing  neces- 
sary equipment  or  improvements,  and  that  the  amount 
is  sufficient  to  start  shipments  by  rail.  The  contract  for 
ore  is  made  usually  at  a  price  slightly  below  the  market 
price,  as  the  lender  is  taking  a  large  risk  while  the  miner, 
of  course,  will  reap  all  the  profit.  The  reputation  of 
the  miner  for  honesty  and  ability  must  be  taken  into  con- 
sideration in  making  such  loans.  At  this  point  a  word 
as  to  fair  play  will  be  in  order.  A  considerable  number 
of  the  loans  made  in  the  manner  outlined  above  has  been 
lost  because  of  duplicity  and  bad  faith.  Litigation  fol- 
lows and  the  mine  ceases  production.  The  United  States 
government,  in  these  critical  times,  cannot  permit  pro- 
duction to  cease  for  such  reasons  as  these,  and  the  owner 
who  becomes  involved  in  these  disputes,  causing  the 
cessation  of  production,  is  little  better  than  a  traitor. 
Honest  difference  of  opinion  may  sometimes  occur,  but 
when  this  happens,  don't  rush  to  the  lawyers  with  your 
trouble.  Sit  down  on  a  log  with  the  'other  fellow'  and 
meet  him  half  way  in  a  fair  discussion.  If  the  difference 
of  opinion  has  no  honest  foundation,  and  would  prevent 
production,  the  facts  should  be  reported  to  the  U.  S. 
Department  of  Justice,  for  the  Government  will  not 
permit  chrome  deposits  to  remain  idle  if  it  can  be  pre- 
vented. 

Markets,  Selling  Conditions,  Future 
Prices.  The  following  schedule  of  prices  was  pub- 
lished in  the  'Engineering  &  Mining  Journal'  on  June 
8,  1918,  and  is  stated  to  be  the  schedule  of  a  large 
purchaser,  f.o.b.  cars  at  stations  on  California  and 
Oregon  main  line  railroads. 


Cr,03 

% 

30     

Price 
Per  Unit 

fO.85 

0  90 

Cr^Oa 
% 
40      

Price 
Per  Unit 
f  1  30 

31      

41      

1  325 

32     

0  95 

42      

43     

1  35 

33     

1.00 

1  375 

34     

1.05 

44      

.  •  .  .         1  40 

35     

1  10 

45      

1  425 

36     

1  15 

46 

1  45 

37     

1.20 

47      

1  475 

38     

1.25 

48     and  upward 

1  50 

39     

1.276 

Another  large   purchaser   gives   the  schedule   below 
—24— 


which  is  somewhat  different.  In  each  case,  the  prices 
were  effective  on  June  1,  1918,  and  are,  of  course,  not 
fixed  for  any  specified  period. 


30 

Price 
Per  Unit 

»0.65 

0  73 

CroOa 
% 
41     

Price 
Per  Unit 
$1.33 

31 

42     

1.34 

33     

0.79 

43     

1.36 

33     

0  86 

44      

1.38 

34     

0  93 

45      

1.40 

35 

1  00 

46      

1.42 

36 

1.10 

1  20 

47             

1  44 

37      

48      

1.46 

38     

1  25 

49      

1.48 

39     

1.275 

50      

1.50 

Contracts.  Contracts  for  ore  are  made  for  periods 
ranging  from  one  month  to  two  years,  most  of  the  buyers 
preferring,  it  is  believed,  to  limit  their  contracts  to  about 
six  months.  A  fixed  schedule  of  prices  is  provided  in  the 
contract,  and  such  prices  remain  effective  during  the 
term  of  the  contract.  The  amount  of  ore  to  be  delivered 
by  the  miner  is  sometimes  specified,  but,  as  it  is  difficult 
to  estimate  the  probable  output  of  a  deposit,  it  is  prefer- 
able that  the  contract  should  call  for  the  entire  produc- 
tion, providing,  if  the  purchaser  prefers,  a  maximum 
amount  to  be  shipped. 

Contracts  should  specify : 
(a)   Situation  and  name  of  mine. 
(5)   Length  of  time  the  contract  is  to  run. 

(c)  "When  deliveries  are  to  start. 

(d)  Amount  of  ore  to  be  sold. 

(e)  Price. 

(/)  Railroad  station  where  the  ore  is  to  be  loaded. 
(g)  Method  of  payment. 

(h)   How  sampling  of  the  shipment  is  to  be  done. 
(i)  Name  of  chemist  whose  analysis  shall  determine 
the  price. 
A  satisfactory  form  of  contract  is  as  follows: 

(Town)    State 

Date  

John  Smith  agrees  to  sell  to  John  Doe  Company  and 

John  Doe  Company  agrees  to  buy   tons  of 

chrome  ore  mined  or  to  be  mined  from  deposits  situated 

,  to  be  delivered  on  cars  at 

at  prices  and  terms  as  follows: 

—25— 


Price: 

$ per  unit  for  ore  containing-  30%  chromic  oxide. 

9 per  unit  for  ore  containing-  31%  chromic  oxide. 

$ per  unit  for  ore  containing-  33%  chromic  oxide. 

3 per  unit  for  ore  containing  33%  chromic  oxide. 

$ per  unit  for  ore  containing  34%  chromic  oxide, 

$ per  unit  for  ore  containing:  35%  chromic  oxide. 

$ per  unit  for  ore  containing  36%  chromic  oxide. 

$ per  unit  for  ore  containing  37%  chromic  oxide. 

$ per  unit  for  ore  containing  38%  chromic  oxide. 

$ per  unit  for  ore  containing  39%  chromic  oxide. 

9 per  unit  for  ore  containing  40%  chromic  oxide. 

$ per  unit  for  ore  containing  41%  chromic  oxide. 

3 per  unit  for  ore  containing  42%  chromic  oxide. 

$ per  unit  for  ore  containing  43%  chromic  oxide. 

9 per  unit  for  ore  containing  44%  chromic  oxide. 

9 per  unit  for  ore  containing  45%  chromic  oxide. 

$ per  unit  for  ore  containing  46%  chromic  oxide. 

$ per  unit  for  ore  containing  47%  chromic  oxide. 

$ per  unit  for  ore  containing  48%  chromic  oxide. 

9 per  unit  for  ore  containing  49%  chromic  oxide. 

9 per  unit  for  ore  containing  50%  chromic  oxide. 

If  the  silica  content  should  exceed  ....%,  ....c. 
per  ton  for  eaeh  one  per  cent  of  silica  in  excess  of 
said  ....  %  shall  be  deducted,  and  buyer  may  reject,  at 
his  option,  any  ore  containing  more  than  ....  %  silica. 
No  ore  shall  contain  less  than  ....  %  chromic  oxide. 

Terms  : 

Payment  in  full     .„  ,  ^  ,   ,. 

.     s   -n  J.    £  or^ry,   will  be  made  upon  presentation 

(or)  Payment  of  80%  ^       f 

at Bank  at of  sight 

draft    and    bill    of    lading    showing    certified    railroad 

weights,  with    invoice    and    certificate    of    analysis    by 

attached  thereto.     If  any  balance  shall 

remain  due,  this  shall  be  paid  within  ten    (10)    days 

from  receipt  of  car  at  destination  and  completion  of 

sampling  and  analysis.    Sampling  by  the  John  Doe  Co. 

Railroad  weights  shall  govern  all  settlements. 

Shipments  : 

Shipments  will  be  started  within   days  from 

date  hereof,  and  completed days  thereafter.    All 

cars  to  be  shipped  to  John  Doe  Company, 

This  contract  is  made  subject  to  such  conditions, 
terms,  and  price,  as  may  in  the  future  be  determined 
by  the  United  States  Government. 

(Signature) 

(Signature)    

John  Doe  Company. 
By 

—26-- 


How  TO  Make  Shipments.  Be  certain  that  you  have 
40  tons,  or  more,  of  ore  at  the  railroad  switch  before 
asking  the  local  railroad  agent  to  deliver  a  car.  Gon- 
dolas are  usually  more  convenient  for  loading,  although 
box-cars  may  be  used  if  gondolas  are  not  available. 
When  the  car  is  spotted,  load  it  promptly.  A  penalty  is 
charged  by  the  railway  company  if  the  car  is  not  loaded 
within  the  time  allowed.  This  may  be  48  hours,  but 
shippers  should  load  in  less  time  than  this.  It  is  of  great 
importance  in  carrying  out  our  war  program  to  have 
cars  loaded  and  shipped  with  great  speed.  Load  the 
cars  to  their  capacity  whenever  possible.  The  local  rail- 
road agent  will  tell  you  the  maximum  capacity  of  the 
car.  The  capacity  printed  on  the  side  of  the  car  is  not 
the  maximum  capacity.  When  the  car  is  loaded,  notify 
the  railroad  agent  that  the  car  is  released  for  shipment. 
The  next  step  is  to  secure  a  bill-of-lading.  Shipments 
should  be  made  on  an  'order  bill-of-lading.'  Remem- 
ber that  the  consignee  shown  in  the  bill-of-lading  owns 
the  ore.  A  shipper  should  ship  the  ore  to  the  destination 
agreed  with  the  purchaser,  but  should  ship  it  to  himself. 
On  the  back  of  the  'order  bill-of-lading'  is  a  space  pro- 
vided for  endorsements.  The  bill-of-lading  should  then 
be  endorsed,  as  in  the  case  of  a  bank  check.  The  en- 
dorsement should  read: 

"Deliver  to  the  order  of  John  Doe  Company. 

John  Smith.'' 

A  copy  of  the  face  of  an  order  bill-of-lading  is  given 
on  page  16. 

Do  not  surrender  the  bill-of-lading  until  your  receive 
payment  for  the  shipment. 

Settlements  are  based  on  the  railroad  weights,  and 
this  the  railroad  company  will  deliver  through  its  local 
agent.  These  weights  should  be  noted  by  the  railroad 
agent  on  the  face  of  the  bill-of-lading,  or  on  a  separate 
certificate  of  weight  furnished  by  him.  Arrangements 
are  usually  made  with  some  local  bank  so  that  the  ship- 
per can  present  to  that  bank  his  bill-of-lading,  showing 
the  railroad  weights,  and  his  certificate  of  analysis,  in 
exchange  for  which  he  receives  cash. 

Some  purchasers  pay  but  80  or  90%  at  the  time  the 

—27— 


shipment  is  made,  the  balance  being  paid  on  receipt  of 
the  car  at  its  destination  or  as  soon  thereafter  as  the 
car  has  been  sampled  and  analyzed.  If  the  shipper 
accepts  such  terms,  he  must  not  be  disappointed  if  his 
final  settlement  is  delayed  for  a  long  period.  Freight 
moves  slowly,  and  the  shipment  may  be  caught  in  em- 
bargoes. 

Specifications  for  Marketable  Ore.  Ore  containing 
28%  or  more  of  chromic  oxide  is  saleable.  If  the  silica 
content  exceeds  8%,  a  penalty  of  25c.  per  ton  for  each 
1%  of  silica  over  8%  is  sometimes  charged,  and  a  maxi- 
mum of  12%  may  be  allowable.  If  the  ore  contains 
more  than  12%  silica  and  the  chromic  oxide  content  is 
fairly  high,  then  the  silica  is  sometimes  permitted  to  ruii 
up  to  15%  or  more.  Special  arrangement  with  pur- 
chasers must  be  made  in  such  cases. 

Occasionally,  though  rarely,  low-grade  ore  may  con- 
tain too  much  iron  to  be  saleable.  There  is  no  fixed 
limit  for  iron,  and  most  contracts  make  no  mention  of 
the  iron  content,  but  iron  in  excess  of  18  or  20%  is  not 
desirable. 

Methods  of  Marketing.  The  sale  of  ore  to  brokers, 
dealers,  and  middle-men  is  not  encouraged.  Consumers 
of  chrome  ore  are  willing  to  buy  direct  from  the  pro- 
ducer, and  the  producer  should  not  be  compelled  to  divide 
his  profit  with  middle-men.  Many  dealers  and  brokers 
are  without  financial  responsibility,  and  some  are  lacking 
in  honesty.  The  miner  and  shipper  have  suffered  so 
much  loss  from  transactions  with  them,  that  a  warning 
should  not  be  necessary. 

A  list  of  some  of  the  consumers  follows: 
American  Refractories  Co.,  Pittsburgh,  Pa.,  and  Mer- 
chants National  Bank  Bldg.,  San  Francisco. 
Binney  &  Smith,  81  Fulton  St.,  New  York,  N.  Y. 
California  Chrome  Co.,  Kohl  Bldg.,  San  Francisco,  Calif. 
Carnegie  Steel  Co.,  Pittsburgh,  Pa. 
Colorado  Fuel  &  Iron  Co.,  Denver,  Colo. 
Crucible  Steel  Co.  of  America,  Pittsburgh,  Pa. 
A.  C.  Daft,  Oliver  Bldg.,  Pittsburgh,  Pa. 
Electro-Metallurgical  Co.,  Niagara  Falls,  N.  Y. 
Harbison-Walker  Refractories  Co.,  Pittsburgh,  Pa. 

—28— 


E.  J.  Lavino  &  Co.,  Bullitt  Bldg.,  Philadelphia,  Pa. 
Lukins  Iron  &  Steel  Co.,  Seattle,  Wash. 
Metal  &  Thermit  Corporation,  120  Broadway,  New  York. 
Mutual  Chemical  Co.,  55  John  St.,  New  York,  N.  Y. 
Noble  Electric  Steel  Co.,  995  Market  St.,  San  Francisco, 

Calif. 
Otis  Steel  Co.,  Cleveland,  Ohio. 
Pacific  Coast  &  Steel  Co.,  San  Francisco,  Calif. 
Pacific  Coast  &  Steel  Co.,  Seattle,  Wash. 
Pacific  Electro  Metals  Co.,  Balboa  Bldg.,  San  Francisco, 

Calif. 
Frank  Samuel,  Harrison  Bldg.,  Philadelphia,  Pa. 
Sawyer  Tanning  Co.,  Napa,  Calif. 
The  Sherwin-Williams  Co.,  Cleveland,  Ohio. 
St.  Louis  Refractories  Co.,   Title  Guaranty  Bldg.,   St. 

Louis,  Mo. 
The  Ferro  Alloy  Co.,  603  Symes  Bldg.,  Denver,  Colo. 
The  National  Electrolytic  Co.,  Niagara  Falls,  N.  Y. 
Youngstown  Steel  &  Tube  Co.,  Youngstown,  Pa. 

The  above  list  is  supplied  by  the  United  States  Geo- 
logical Survey,  and,  while  doubtless  not  complete,  con- 
tains all  the  names  of  which  the  Survey  has  a  record. 

Some  of  the  above  concerns  maintain  representatives 
on  the  Pacific  Coast  with  whom  direct  contact  may 
be  had. 

Present  and  Future  Markets.  If  chrome  ore  were 
plentiful  enough  to  supply  the  demand,  there  would  be 
used  in  the  United  States  in  1918,  between  150,000  and 
200,000  tons.  Because  of  our  inability  to  produce  this 
amount,  the  consumption  has  been  restricted  to  some 
extent  by  Governmental  action.  The  use  of  chrome  ore 
by  several  industries  has  been  reduced  in  this  way,  and 
f erro-chrome,  an  allay  made  from  chrome  ore,  may  be 
used  at  present  only  in  Government  work.  This  will 
reduce  the  demand  to  some  extent.  More  chrome  will 
be  required,  however,  than  can  be  produced.  The  ques- 
tion is  constantly  being  asked,  'How  long  will  these 
prices  prevail?*  It  is  not  believed  that  there  will  be  a 
substantial  decrease  in  price  as  long  as  the  War  con- 
tinues.   How  long  this  may  be  is  a  matter  of  conjecture. 

—29— 


Sampling  and  Analysis  of  Chromite 


By  ABBOT  A.  HANKS 

Preparation  of  Samples.  The  sample  sent  to  the 
assayer,  if  it  represents  either  a  shipment  or  a  lot  of  ore 
extracted  for  shipment,  should  be  taken  so  as  to  repre- 
sent what  it  is  intended  to  sample.  It  should  weigh  40 
to  60  lb.,  and  contain  no  single  piece  larger  than  an  egg. 
When  this  sample  reaches  the  laboratory  it  should  all 
be  crushed  through  a  rock  breaker,  set  to  give  a  one-half 
inch  product.  The  rock-breaker  product  should  be 
thoroughly  mixed  and  cut  down  with  a  riffle,  a  Jones 
divider,  or  similar  sampler,  to  one-quarter  of  its  original 
size.  This  quarter  (10  to  12  lb.)  should  be  put  through 
laboratory  rolls,  set  to  give  a  product  of  12  to  16-mesh. 
This  roll-product  should  again  be  cut  down  to  a  sample 
of  about  one  pound.  The  whole  of  this  one-pound  sample 
should  be  pulverized  in  a  disc-grinder  or  similar  ma- 
chine to  pass  100  or  150-mesh.  Before  making  the 
analysis  the  pulp  should  be  dried  at  212  °F.  to  constant 
weight. 

Chromium 

The  analysis  of  chrome  ore  may  be  separated  into  the 
following  operations: 

Fusion  in  an  iron  cnicible  with  sodium  peroxide. 

Dissolving  the  melt  in  water;  filtering  and  making 
acid  with  sulphuric  acid. 

Adding  an  excess  of  ferrous  ammonium  sulphate  and 
titrating  with  standard  potassium  permanganate  solu- 
tion. 

The  standard  method  is  described  in  the  following 
text-books : 

' '  Technical  Methods  of  Ore  Analysis, ' '  by  A.  H.  Low. 

''Standard  Methods  of  Chemical  Analysis,"  by  W.  W. 
Scott. 

''Principles  of  Quantitative  Analysis,"  by  W.  C.  Bias- 
dale. 

Weigh  out  I  gram  of  100  to  150-mesh  product;  place 
in  a  20-cc.  iron  crucible;  add  8  gm.  sodium  peroxide 
and  mix  thoroughly  with  a  small  glass  rod;  cover  and 

—30— 


slowly  fuse  over  a  Bunsen  burner  by  slowly  rotating 
over  the  flame  for  about  five  minutes;  when  complete, 
decomposition  of  the  ore  will  result.  When  partly 
cool,  transfer  the  crucible  and  the  melt  to  a  400-cc. 
beaker  containing  150  cc.  to  200  cc.  water.  When 
action  ceases,  rinse  the  crucible  and  the  cover,  then  boil 
the  solution  at  least  five  minutes,  then  dilute  to  350  cc. 
with  hot  water.  When  partly  cool,  filter  and  wash  thor- 
oughly with  hot  water.  Dissolve  the  precipitate  with 
dilute  hydrochloric  acid  to  determine  if  the  fusion  was 
complete.  If  not,  start  a  new  portion.  Cool  the  filtrate, 
transfer  to  a  1000-cc.  beaker  and  dilute  to  500  cc.  with 
cold  water,  and  add  25  cc.  sulphuric  acid  (2  to  1)  ;  add 
50  cc.  standard  ferrous  ammonium  sulphate  solution, 
from  an  automatic  pipette,  to  the  solution  in  the  beaker 
and  then  titrate  w^ith  standard  potassium  permanganate 
solution.  Standardization  is  accomplished  by  weighing 
J  gm.  of  c,p.  potassium  chromate  into  a  1000-cc.  beaker, 
dissolve  in  cold  water,  and  make  acid  as  above  and  pro- 
ceed as  explained;  50  cc.  of  the  ferrous  ammonium  sul- 
phate- solution  is  titrated  at  least  once  each  day  by  the 
potassium  permanganate  to  determine  their  relative 
strength. 

Potassium  chromate  equals  39.135%  CraOg. 

Ferrous  ammonium  sulphate  solution  contains  100  gm. 
ferrous  ammonium  sulphate  crystals  and  20  cc.  sulphuric 
acid  per  litre. 

Potassium  permanganate  solution  contains  6.0  gm. 
c.p.  KMn04  per  litre. 

1  gm.  potassium  chromite  equals  26.25  cc.  KMn04. 

69.45 
26.25 


43.20 


86.40/  ^  ff  V^^  CQuals  0.0045296  g^rams  Cr.,03  equals  value  of  1  cc.  KMnOi 
06.4 

Silica 

One-half  gram  of  ore  is  fused  as  above;  dissolve  in 
50  cc.  water;  rinse  off  the  crucible  and  the  cover;  make 
acid  with  hydrochloric  acid,  and  take  to  dryness  twice 
as  for  silica  determinations.  Complete  as  usual  for 
silica. 

—31— 


The  Determination  of  Chromium  in  Chromite 

The  following  rapid  method  is  in  use  at  the  Berkeley 
Experiment  Station  of  the  U.  S.  Bureau  of  Mines : 

The  ore  should  be  ground  to  100-mesh.  Weigh  out 
0.5  gm.  sample  and  brush  into  a  20-cc.  spun-iron  crucible 
in  which  has  previously  been  placed  4  to  5  gm.  of  fresh 
NaaOa  (technical  grade  is  satisfactory).  Mix  well  with 
a  glass  rod,  cover  with  a  little  NasOs  and  fuse  at  a  low- 
red  heat.  After  the  charge  has  melted  it  should  remain 
in  the  molten  condition  for  five  minutes.  Allow  the 
crucible  to  cool,  place  in  a  600-cc.  beaker  of  pyrex  or 
other  low-expansion  glass  or  in  a  large  casserole;  add 
water  and  digest  until  the  fused  mass  has  disintegrated, 
after  which  remove  and  rinse  the  crucible.  Boil  for  10 
minutes  to  decompose  the  NaoOo.  Without  filtering, 
neutralize  the  solution  with  1-4  HgSO^  or  1-1  HCl  and 
add  25  to  30  cc.  excess.  Dilute  to  approximately  400  cc, 
cool  and  titrate  with  a  standard  solution  (about  0.2  N) 
of  FeS04.  Add  a  slight  excess  of  FeSO^  solution,  as 
shown  by  spot-plate  tests  with  a  1%  solution  of 
K3Fe(CN)6,  and  finish  the  determination  by  back-titra- 
tion  with  standard  K2Cr207  solution.  The  FeS04  solu- 
tion may  be  added  rapidly  without  great  care,  as  the 
approximate  end-point  is  readily  recognized  by  the 
color-change  of  the  solution.  With  a  little  practice  two 
or  three  spot-tests  should  be  sufficient  to  determine  the 
exact  end-point. 

Notes:  The  quickness  of  this  method  is  due  largely  to 
the  omission  of  filtration  before  acidifying  the  dissolved 
fusion.  Manganese  is  practically  the  only  interfering  sub- 
stance found  in  Western  ores,  and  when  this  is  present 
filtration  is  necessary. 

The  initial  alkaline  solution  containing  the  precipitate  in- 
clines to  bump  on  boiling.  A  few  chips  of  fresh  unglazed 
porcelain  or  a  stirring-rod  with  roughened  end,  placed 
opposite  one  of  the  points  where  the  beaker  makes  contact 
with  the  hot  plate,  minimizes  this  difficulty. 

The  standard  FeS04  solution  is  prepared  by  dissolving  56 
to  60  gm.  FeS04-7H,0  in  about  800  cc.  distilled  H.O,  to 
which  has  been  added  100  cc.  concentrated  HoSO^.  After 
cooling,  the  solution  is  diluted  to  one  litre.  The  0.2  N 
KoCr,07  solution  may  be  made  by  dissolving  9.806  gm.  c.p. 
K.CraOT  in  one  litre.  The  FeSO,  solution  may  be  standard- 
ized with  a  standard  KMnOi  solution  based  on  Bureau  of 
Standards  sodium  oxalate  or  against  the  KoCraOr  solution, 
provided  this  was  made  from  a  salt  of  known  purity. 

One  cubic  centimetre  of  0.1  N  solution  is  equivalent  to 
0.001733  gm.  Cr,  or  0.002532  gm.  CrA- 

—32— 


YC"  15033 


^^ 


3873G2 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


